Gun-barrel



A. W. THISTLETHWAITE.

GUN BARREL.

AP I918- 1,35 1,309. ate ted Aug. 31, 192%.

UNETEQ STATES ARTHUR W. THIS'ILETHWAITE, F ATCI-IISON, KANSAS.

GUN-BARREL.

Specification of Letters Patent.

Patented Aug. 31, 1920.

Application filed June 4, 1918. Serial No. 238,160.

To all whom it may concern:

Be it known that I, ARTHUR W. THIsrLE- THWAITE, a citizen of the UnitedStates, residin at Atchison, in the county of Atchison and State ofKansas, have invented certain new and useful Improvements inGun-Barrels, of which the following is a specification.

My invention has special reference to shot guns and other smooth boreweapons, the object of the invention being to provide a gun barrel whichwill concentrate the shot so as to prevent the scattering or crossing ofthe same without unduly retarding the discharge of the missiles from thegun.

In the accompanying drawings,

Figure 1 is a longitudinal section of a gun barrel constructed inaccordance with my present invention,

Fig. 2 is a similar view of another form.

In the drawing, the reference numeral 1 denotes a gun barrel which is ofthe usual material and may be of any preferred dimensions. The rearportion 2 of the bore of the barrel is tapered from the breech end 3toward the muzzle end 4 for a distance which is shown as about one-thirdof the entire length of the barrel, the tapered bore terminatin at apoint 5. From the point 5 to the mout or muzzle of the barrel, the boreis cylindrical, as shown at 6. The relative lengths of the tapered andcylindrical bores may be varied according to the dimensions of the gunand the nature of the ammunition which is to be employed, butpractically the tapered portion should not be less than onethird of theentire length of the barrel and will seldom be more than two-thirds thelength of the barrel.

By providing a tapered bore from the breech forwardly, I effect achoking of the charge of shot without unduly retarding the propulsion ofthe same but effect sufficient compression to insure hard shooting andby having a cylindrical bore at the muzzle end of the barrel I preventthe shot crossing or scattering excessively so that the missiles willcarry upon parallel lines for a considerable distance and the gun willbe particularly adapted for firing heavy shot at a considerable range.

In Fig. 2, the gun barrel is provided with a sharply tapered or chokebore 8 at the breech while the forward portion 9 of the bore, extendingto the muzzle, is slightly tapered. This form may be preferred with fineor the smaller sizes of shot.

My improved gun barrel may be produced at as low a cost as any gunbarrel now in use and when in use will give more satisfactory resultsthan the choke barrels or the continuous cylindrical barrels which arenow upon the market. By having a sharp breech choke with a cylindricalor nearly cylindrical muzzle portion I am enabled to compress the chargewithout being under the necessity of making the entire barrel extrastrong and, therefore, heavy.

Having thus described my invention, what 'is claimed asnew is: v

1.- A smooth bore gun barrel of greater cross sectional diameter at itsbreech end than at its discharge end and having its bore graduallytapered from the extreme rear end of its breech inthe'direction of itsdischarge end for a distance not less than onethird nor more thantwo-thirds its length, the walls of the bore being of greater thicknessat the breech end of the barrel than at the discharge end thereof,

2. A smooth bore gun barrel of greater cross sectional diameter at itsbreech end

